Projectile tip

ABSTRACT

A projectile includes a body having rotationally axial symmetry; and a meplat at a tip end of the body. The meplat includes a flat portion defined by a plane that intersects the projectile perpendicularly with respect to a central axis through a lengthwise direction of extension of the projectile, and a chamfered portion defined by a chamfer cut extending from an outer perimeter of the flat portion toward an outer surface of the body.

CROSS REFERENCE TO RELATED PATENT APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 62/569,383, filed Oct. 6, 2017, the content of which is incorporated herein by reference.

BACKGROUND

In the anatomy of a bullet, the meplat is a small flat area at the outer tip of the head of the bullet. Many rifle rounds implement a meplat. In the case of copper-jacketed rounds, a meplat may form as a side effect of the manufacturing process, when molten lead is injected into the copper jacket. With respect to solid, single material (i.e., monolithic) bullets, the tip of the bullet may be deliberately cut to a particular diameter. Generally, from an aerodynamic perspective, the smaller the meplat of the bullet, the better the bullet performs aerodynamically. However, as the meplat decreases in size, the difficulty in manufacturing increases.

Conventionally, several different bullet tip meplat designs are used, including: a small round tip, an infinitesimally sharp (pointed) tip, and a tip having an aggressive downslope close to the tip. Each of the conventional designs suffer from various flaws, such as difficulty in the manufacturing process which leads to inconsistency in production for consistent reliable performance.

The small round tip is very difficult manufacture it correctly. Frequently, slight changes in tooling will have significant effects on the geometry of the tip. In addition, extensive testing shows that when firing rounds with the small round tip meplat design, the shot placement accuracy tends to be less than for rounds having a simple meplat.

Even more challenging to manufacture than the small round tip meplat is an infinitesimally sharp (pointed) tip meplat. This tip design suffers from the same accuracy issues described above with respect to the small round tip meplat. In addition, due to the minimized strength of the tip inherent in the material when reduced to such a small shape, the tips are prone to damage caused by collisional movements, such as may occur during the loading operation of the round to a firearm's chamber when shooting. This damage, in the form of flattened and/or bent tips may affect consistency in placement accuracy as well.

While the meplat of an aggressive downslope close to the tip allows for a heavier, thicker cone, this design creates extra pressure at the tip. Moreover, this tip design also suffers from the same accuracy issues described above.

Thus, compared with and in view of the above concerns with other meplat designs, a simple meplat may be easier to manufacture and may provide for more consistent shot placement accuracy and reliability when fired.

BRIEF DESCRIPTION OF THE DRAWINGS

The Detailed Description is set forth with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items. Furthermore, the drawings may be considered as providing an approximate depiction of the relative sizes of the individual components within individual figures. However, the drawings are not to scale, and the relative sizes of the individual components, both within individual figures and between the different figures, may vary from what is depicted. In particular, some of the figures may depict components as a certain size or shape, while other figures may depict the same components on a larger scale or differently shaped for the sake of clarity.

FIG. 1 illustrates a perspective view of a meplat tip according to an embodiment of the instant disclosure.

FIG. 2 illustrates a side view of the meplat tip according to FIG. 1.

FIG. 3 illustrates a side view of three different meplat tips showing pressure build up at the tip of three different bullet tips in a flow simulation at 2500 feet per second (fps).

DETAILED DESCRIPTION Overview

This disclosure is directed to an improved meplat tip design for decreasing pressure build-up and thus turbulence on a projectile. That is, consistent with the title of this disclosure, it is contemplated that other types of projectiles beyond bullets may employ a meplat as disclosed herein.

In an example projectile, the implementation of the meplat described herein, is described with respect to improving consistency and accuracy of a fired bullet. At least one of the following advantages may be achieved with the implementation on a projectile of a meplat according to an embodiment of the instant disclosure. For example, advantages of a bullet having a meplat according to an embodiment of the instant disclosure compared to bullets having conventional meplats (e.g., bullets with a small rounded meplat, an infinitesimally sharp (pointed) tip meplat, a meplat of an aggressive downslope close to the tip, etc.) may include: easier manufacturing; superior aerodynamic performance; increased durability; improved loading capability; etc., each of which assist in superior shot placement accuracy, when the meplat is discussed in terms of a bullet as the projectile.

Illustrative Embodiment of a Meplat Tip

Specifically, FIG. 1 depicts an upper end of a bullet head 100 with a perspective view of a meplat 102 according to an embodiment of this disclosure. FIG. 2 depicts a side view of the bullet head 100 having the meplat 102. As shown, meplat 102 is defined by a flat portion 200 and a chamfered portion 202. The flat portion 200 of the meplat is defined such that the flatness is aligned with a plane that intersects the bullet head 100 perpendicularly with respect to a central axis through the lengthwise direction of extension of the bullet head 100. Thus, inasmuch as the shape of the bullet head 100 is rotationally symmetrical about the central axis, the flat portion 200 is a circular surface on the tip of the bullet head 100. The chamfered portion 202 is a chamfer cut at an angle “a” from the edge of the flat portion 200 to the outer surface of bullet head 100.

In bullets having a small to medium sized rifle caliber, (e.g., .223, 300BLK, .308Win, etc.), flat portion 200 may have a diameter dimension (i.e., equal to 2*r) of about 0.4 mm. In an embodiment, the diameter dimension of flat portion 200 may range from about 0.35 mm to about 0.45 mm. Using a chamfer angle “a” ranging from about 51 degrees to about 53 degrees (based on the caliber and the ogive), such as, for example, 52.5 degrees, a chamfer depth “d” may be about 0.1 mm.

In larger caliber rifle bullets (e.g., .338, 50cal, etc.), an embodiment of the flat portion 200 may have a diameter (2*r) that ranges from about 0.4 mm to about 0.7 mm. Further, for the larger caliber rifle bullets, the chamfer depth d may range from about 0.1 mm to about 0.3 mm, for example.

FIG. 3 depicts a flow simulation illustrating the pressure build up on three different bullet heads: bullet head 300 having a conventional, small round meplat tip; bullet head 302 having a conventional, simple meplat that is just a flat surface end; and a bullet head 304 having a meplat according to an embodiment of the instant disclosure including the chamfer cut around the flat surface end. The simulation is performed under a condition of flow at 2500 fps, and the bullet head 300 and the bullet head 302 have a traditional meplat size of 0.75 mm. Within the flow simulation program used to provide the images of FIG. 3, generally the simulation images display a variety of colors to better inform a user of the results of varying flow pressure experienced by the objects (e.g., projectiles 300, 302, and 304) under simulation. Here, however, as the images in FIG. 3 are in black and white only, it should be understood that the darkness of a given spot on the image is indicative of the degree of pressure experienced. Further, the pressure scale depicted herein is to be understood as going from less pressure starting at a lightest shade to increasing pressure as the shade gets darker.

Turning to the results shown in the images of FIG. 3, notice the intensity (i.e., darker shade of grey 306 (bullet head 300) to black 308 (bullet head 302)) of the pressure on the meplat tips of bullet head 300 and the bullet head 302. Both are much darker in shade than the much smaller area and lighter shade 310 of amount of pressure showing on the bullet head 304, indicating a comparatively significant reduction in pressure for the bullet head 304.

Accordingly, a projectile implementing a meplat according to the instant disclosure may have significant advantages including superior aerodynamic performance.

CONCLUSION

Although several embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the claims are not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the claimed subject matter. 

What is claimed is:
 1. A projectile, comprising: a body having rotationally axial symmetry; and a meplat at a tip end of the body, the meplat including: a flat portion defined by a plane that intersects the projectile perpendicularly with respect to a central axis through a lengthwise direction of extension of the projectile, and a chamfered portion defined by a chamfer cut extending from an outer perimeter of the flat portion toward an outer surface of the body.
 2. The projectile according to claim 1, wherein the projectile is a bullet of a predetermined caliber.
 3. The projectile according to claim 2, wherein a diameter dimension of the flat portion is based on the predetermined caliber of the bullet.
 4. The projectile according to claim 3, wherein the diameter dimension of the flat portion ranges from about 0.35 mm to about 0.7 mm.
 5. The projectile according to claim 3, wherein the diameter dimension of the flat portion ranges from about 0.35 mm to about 0.45 mm.
 6. The projectile according to claim 3, wherein the diameter dimension of the flat portion is 0.4 mm.
 7. The projectile according to claim 2, wherein an angle of the chamfer cut is based on the predetermined caliber of the bullet.
 8. The projectile according to claim 7, wherein the angle of the chamfer cut ranges from about 51 degrees to about 53 degrees.
 9. The projectile according to claim 7, wherein the angle of the chamfer cut is 52.5 degrees.
 10. The projectile according to claim 2, wherein a depth of the chamfer cut is based on the predetermined caliber of the bullet.
 11. The projectile according to claim 10, wherein the depth of the chamfer cut ranges from about 0.1 mm to about 0.3 mm.
 12. The projectile according to claim 10, wherein the depth of the chamfer cut is 0.1 mm.
 13. A bullet, comprising: a body having rotationally axial symmetry; and a meplat at a tip end of the body, the meplat including: a flat portion defined by a plane that intersects the projectile perpendicularly with respect to a central axis through a lengthwise direction of extension of the projectile, a diameter dimension of the flat portion being based on a predetermined caliber of the bullet, and a chamfered portion extending from the flat portion.
 14. The bullet according to claim 13, wherein the diameter dimension of the flat portion ranges from about 0.35 mm to about 0.7 mm.
 15. The bullet according to claim 13, wherein the diameter dimension of the flat portion ranges from about 0.35 mm to about 0.45 mm.
 16. The bullet according to claim 13, wherein the diameter dimension of the flat portion is 0.4 mm.
 17. A bullet, comprising: a body having rotationally axial symmetry; and a meplat at a tip end of the body, the meplat including: a flat portion, and a chamfered portion extending from an outer perimeter of the flat portion toward an outer surface of the body, the chamfered portion having a depth and a cut angle that are each based on a predetermined caliber of the bullet.
 18. The bullet according to claim 17, wherein the cut angle of the chamfered portion ranges from about 51 degrees to about 53 degrees.
 19. The bullet according to claim 17, wherein the cut angle of the chamfered portion is 52.5 degrees.
 20. The bullet according to claim 17, wherein the depth of the chamfered portion ranges from about 0.1 mm to about 0.3 mm. 